In a battery block of recent years, a number of battery cells are arranged and secured with spacers disposed between the battery cells, and the end faces of the blocks are covered and secured by end plates. The end plates are formed in a size such that the battery cells exposed on the end faces can be covered. The end plates secure the battery cells by holding them integrally from both sides thereof in a direction in which the cells are arranged. Gas for cooling the battery cells is passed through gaps formed between the battery cells and between the battery cells and the end plates. The gas absorbs heat from the battery cells, thereby cooling the battery cells (see Patent Literature 1, for example).